The purpose of the work described in this proposal is to continue to study the mechanisms of cellular immunity and hypersensitivity. Our aim is to acquire knowledge of the basic mechanisms that are recruited and activated, which can be used to rationally manipulate these cellular processes. Information gained would be applicable to human clinical conditions where enhancement of cellular immunity might lead to prevention or alleviation of disease, such as infections or neoplasia, or where suppression might diminish injury to tissue caused by cellular hypersensitivity. In this proposal, we plan further studies on a macrophage receptor for migration inhibitory factor (MIF); to produce antibodies to MIF; to continue studies on the purification and characterization of human MIF and its relationship to interferon and macrophage activating factor (MAF); further studies on the activation of human macrophages with MAF; and to determine whether autoimmunity induced to collagen by antigen coupled spleen cells can be suppressed in a rat model.